The invention relates generally to electromagnetic valve actuators for controlling valve operation. More particularly, the invention relates to electromagnetic actuators for controlling valve timing in compressors.
One technique to control the load of large compressors is to actively control the opening time of the suction valves of the compressor. When the load on the compressor is low, the suction valves are kept open for a longer period of time compared to compressors handling higher loads. Typically for a no-load condition, the suction valves of the compressor are kept open for the entire period of operation. In a reverse situation, for a full load condition, the suction valves operate without any active control on the opening and closing of the valves.
Currently, either pneumatic or hydraulic actuators establish active control of opening time of the suction valve. Both techniques need a separate supply of hydraulic/gas pressure and oil/gas pressure pipes to connect each actuator to the supply system, which supply system is expensive and has to be maintained regularly. Furthermore, pneumatic actuators cannot achieve high actuation speeds and may not be suitable to be used for continuous control of valve position in each compression cycle.
Therefore there is a need for an efficient, inexpensive and low maintenance actuator for controlling the valves in a compressor.